Age curve

According to Beard (1874), creative achievement tends to increase rapidly up to a peak (acme) just before age 40 and then declines very slowly to almost nothing by age 80. Lehman (1953), who studies the relationship between age and achievement, found out that in most instances the peak productive age occurs around age 40 plus or minus about five years; the creator ascends to this peak rapidly from around the mid-twenties and then descends more gradually.

The main features of the age curve are as follows: 1) output begins in the 20s; 2) for that starting point, the curve ascends quickly to an optimum at some point near 40th year, plus or minus five years; 3) after the career optimum is reached, the curve turns around and gradually approaches the point of zero output rate. Simonton (1994: 183) notes that "Because the decline is not nearly so precipitous as the ascent, creative individuals can be more productive in their 70s than they were in their 20s. Even so, the output rate is about half that seen at the peak career."

The shape of the age curve and the specific location of the peak vary from one creative discipline to another. Lehman (1953) showed that even within a single discipline the age function may vary dramatically according to the particular type of creativity attempted. Thus, creativity in mathematics or poetry tends to peak much earlier than creativity in philosophy or geology; and the peak for writing literary prose comes later that that for writing poetry.

A single-peak age curve predicts more than 90 percent of the longitudinal variance in creative productivity. However, sometimes more than one productive peak is observed in the age functions. (Simonton, 1984)